KR100393686B1 - Rotary actuator with cushion mechanism - Google Patents

Abstract

A rack reciprocally driven by pneumatic pressure, a pinion engaged with the rack, and a cushion mechanism for buffering the rack at a stroke end of at least one of the forward and reverse sides. An exhaust port opening in the pressure chamber at the position, a flow rate adjusting mechanism for controlling the flow rate of the exhaust gas discharged from the exhaust port, and an outer peripheral surface of the piston, and the port hole being directed to the pressure chamber immediately before the piston reaches the stroke end. And a cushion packing operative to shut off the air in the pressure chamber from the outlet through the flow control mechanism.

Description

Rotary actuator with cushion mechanism {ROTARY ACTUATOR WITH CUSHION MECHANISM}

The present invention relates to a rotary actuator with a cushioning mechanism capable of buffering the main shaft rotating reciprocally to the rotary stroke end.

There is a rack pinion type rotary actuator that generates rotational force by air pressure. This rack pinion type rotary actuator slidably inserts a rack-mounted piston into the cylinder tube, engages the pinion in the rack, and reciprocates the rack by applying air pressure to the pressure chamber partitioned on both sides of the piston, And the main shaft fixed thereto.

In a conventional rotary actuator of this kind, a mechanical cushioning mechanism including a dump or the like is provided in order to absorb the impact force caused by the inertia energy of the piston when the main shaft stops at the rotational stroke end. By the way, such mechanical cushioning mechanisms have a problem that there is an impact sound at the time of stopping, deterioration due to abrasion is likely to proceed at the colliding part, or parts such as dumps protrude outwards and interfere with each other. Such a problem can be solved if it becomes possible to provide a pneumatic cushion mechanism instead of the mechanical cushion mechanism.

As such a pneumatic cushioning mechanism, conventionally, during operation of a piston sliding in a cylinder tube, the cushion air is temporarily blocked by a pressure in the exhaust chamber on the exhaust side, and the pressure is increased. It is known to stop bufferingly. This configuration prevents the passage of air by inserting the cushion ring provided on the piston side into the cushion packing in the cylinder tube immediately in front of the stroke end, and introduces the blocked air into the throttle valve, and according to this shrinkage control amount. In this case, the piston back pressure converts the kinetic energy of the piston into the compressed energy of the air to exert the deceleration force.

However, the cushion mechanism using such a piston back pressure is required to provide a cushioning of a predetermined length on at least one side of the piston and to provide a long empty chamber in which the cushioning is inserted into the cylinder tube. Inevitably, there is a problem that the length of the cylinder in the axial direction becomes long. Therefore, when this cushioning mechanism is used for a rack pinion type rotary actuator, the rotary actuator which becomes structurally long in the direction orthogonal to a main axis will be lengthened further in that direction.

The main object of the present invention is to provide a rack pinion type rotary actuator provided with a pneumatic cushion mechanism.

Another object of the present invention is to construct a rack pinion type rotary actuator having a length in a direction perpendicular to the rotational spindle structurally so that its length does not become longer even by installation of the cushioning mechanism.

Another object of the present invention is to provide a rotary actuator with a compact, simple and inexpensive rack pinion type cushion mechanism by eliminating the long cushioning and the long vacancy in which it is fitted.

In order to achieve the above object, according to the present invention, there is provided a rack reciprocally driven by pneumatic pressure, a pinion engaged with the rack, and a cushioning mechanism for buffering the rack at a stroke end of at least one forward and reverse position. Rack pinion type rotary actuators are provided.

The cushioning mechanism is provided in the pressure chamber for driving the rack at an exhaust port opening at a position of a thread end portion rather than a port hole, a flow rate adjustment mechanism for limiting the flow rate of exhaust gas discharged from the exhaust port, and an outer peripheral surface of the piston, A cushion packing is operable to shut off the port hole from the pressure chamber immediately before the piston reaches the stroke end and to discharge the air in the pressure chamber from the outlet through the flow rate adjusting mechanism.

In the rotary actuator of the present invention having the above structure, the rack is driven reciprocally by supplying compressed air to each other from the ports to the pressure chambers on both sides of the rack, followed by the pinion to reciprocate. At this time, the deceleration stop by the cushion mechanism at the stroke end of the rack is performed as follows. That is, at the time of sliding of the rack, the compressed air in the pressure chamber on the exhaust side is mainly discharged through the port hole. However, when the rack is close to the stroke end and the cushion packing passes the port hole, The pressure chamber is shut off, and the exhaust from the pressure chamber is restricted to be discharged through the flow regulating mechanism only from the exhaust port. For this reason, the exhaust pressure in the pressure chamber rises, and this becomes the back pressure, and the rack reaches the end of stroke while decelerating.

Thus, according to the present invention, a rack pinion type rotary actuator provided with a pneumatic cushion mechanism can be obtained. In addition, since there is no need to provide a long cushioning ring having a conventional cushioning mechanism, a long vacancy in which it fits, etc., the actuator can be shortened in the axial direction of the cylinder by that much, and a compact and simple actuator can be obtained.

According to a preferred embodiment of the present invention, the discharge port is connected to one port via the flow rate adjusting mechanism.

The flow rate adjusting mechanism is formed by a throttle hole for limiting the flow rate of the exhaust gas discharged from the pressure chamber, and in parallel with the throttle hole, an air supply to block the flow of the exhaust gas discharged from the pressure chamber or flow into the pressure chamber. A check valve is installed to allow flow.

According to a specific embodiment of the present invention, a valve chamber for connecting the outlet and the port is formed in the casing, and a hole member for holding the throttle hole is formed in the valve chamber so that the check valve is formed between the seal wall. The throttle hole and the check valve are combined in the valve chamber by inserting the lip seal.

The rotary actuator of the present invention may be a single rack type having one rack or a double rack type having two racks.

In a double rack rotary actuator, the first pressure chamber and the second pressure chamber are partitioned on both sides of the two racks, and the first pressure chamber of the first rack and the second pressure chamber of the second rack are connected to the first port. In addition, the first pressure chamber of the second rack and the second pressure chamber of the second rack are connected to the second port. In addition, two sets of cushioning mechanisms are provided to buffer the two racks at one stroke end, respectively.

According to a preferred specific embodiment of the present invention, the casing of the actuator has end covers at both ends thereof, so that the two ports are provided at one first end cover, and the second end cover is provided at the second end cover. In addition to the combination of the flow rate adjusting mechanism in the cushion mechanism of the tank, the exhaust port opening in the second pressure chamber is provided, and the port and the flow rate adjusting mechanism communicate with each other through the passage holes formed in the casing, and the passage hole. The port hole branches from the opening to open the hole surface of the cylinder hole.

1 is a partial sectional view showing a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1.

3 is an enlarged view illustrating main parts of FIG. 1.

4 is a cross-sectional view showing a second embodiment of the present invention.

5 is an enlarged view illustrating main parts of FIG. 4.

6 is a sectional view showing the main parts of another embodiment of the flow regulating mechanism.

7 is a sectional view showing the principal parts of still another embodiment of a flow regulating mechanism.

Fig. 8 is a sectional view showing the main parts of still another embodiment of the oil adjustment mechanism.

(Explanation of symbols for the main parts of the drawing)

1A. Actuator 2... cushion

3, 4... End cover 5. Cylinder hole

6. Rack 7a, 7b... piston

8a, 8b... Pressure chamber 10.. Pinion

11. Spindle 12. bearing

14, 15... Port holes 18a, 18b... Cushion mechanism

19. Exhaust port 20. Flow control mechanism

22. Throttle hole 23. Check valve

24. Valve chamber 25. Hole

26. Through-hole 29. You guys

30. Packing P ₁ , P ₂ . port

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail based on drawing. In describing an embodiment, those having the same function will be described with the same reference numerals.

1 to 3 show a first embodiment of the rack pinion type rotary actuator according to the present invention, wherein the actuator 1A is a single rack type.

This actuator 1A has a rectangular cushion 2. The cushion 2 is formed by one cylinder hole 5 whose both ends are closed by the end covers 3 and 4, and a first piston 7a and a second piston 7b provided at both ends thereof. 5) a rack 6 reciprocating and sliding inside, two first and second pressure chambers 8a and 8b partitioned by the pistons 7a and 7b on both sides of the rack 6, and these The first and second two ports P ₁ and P ₂ for supplying compressed air to the pressure chambers 8a and 8b and reciprocating by the reciprocating drive of the rack 6 in engagement with the rack 6 A rotating pinion 10 and a main shaft 11 fixed to the pinion 10 and rotatably supported by the bearing 12 are provided.

The two ports P ₁ and P ₂ are provided at positions of both end portions in the axial direction of the side surface of the cushion 2, and each of the two ports P1 and P ₂ has a cylinder hole (1) in one of the two pressure chambers 8a and 8b. It communicates through the port holes 14 and 15 opening to the hole surface of 5). In addition, by supplying compressed air to each of the pressure chambers 8a and 8b from these ports P ₁ and P ₂ , the rack 6 reciprocates in the cylinder hole 5 together with the pistons 7a and 7b. With this, the pinion 10 and the main shaft 11 fixed thereto are reciprocally rotated.

This actuator 1A further includes first and second two sets of cushioning mechanisms 18a and 18b for buffering the rack 6 at both forward and reverse stroke ends.

The cushion mechanisms 18a and 18b are provided at positions adjacent to one of the ports P ₁ and P ₂ , respectively, and the pressure chambers 8a and 18b are positioned near the pressure chamber ends than the respective port holes 14 and 15. An exhaust port 19 opening in the opening 8b and a flow rate adjusting mechanism provided between the exhaust port 19 and the ports P ₁ and P ₂ to limit the flow rate of the exhaust gas discharged from the pressure chambers 8a and 8b. It has 20.

As shown typically by the cushion mechanism 18b on the side of the port P ₂ in Fig. 3, the flow rate adjusting mechanism 20 is formed of a throttle hole 22 for limiting the exhaust flow rate. In parallel with (22), a check valve (23) for preventing the flow of exhaust gas not flowing back into the throttle hole (22) is connected, and these throttle holes (22) and the check valve (23) are cushioned (2). It is housed in the valve chamber 24 formed in the. In other words, the valve chamber 24 is formed on the side surface of the cushion 2 to communicate with the outlet 19 and the ports P ₁ and P ₂ . The cylindrical cylindrical hole member 25 is accommodated, the throttle hole 22 is provided in the hole member 25, and the outer peripheral surface of the front end of the hole member 25 and the inner peripheral surface of the valve chamber 24 are provided. The lip seal which forms the said check valve 23 is inserted between and. 26 is a through hole connecting the ports P ₁ and P ₂ to the valve chamber 24.

The throttle hole 22 is formed to connect the exhaust port 19 and the ports P ₁ and P ₂ so that the opening area can be adjusted by the needle 29 provided in the hole member 25. have. Therefore, this throttle hole 22 is a variable shaft type which can adjust the flow volume of exhaust gas.

On the other hand, the check valve 23, in the cushion stroke at the stroke end of the rack 6, exhaust from the pressure chamber (8a, 8b) through the throttle hole (22) port (P ₁ , P ₂₎ Except for flowing to the side), the block 6 is blocked, and at the start of driving the rack 6, compressed air from the ports P ₁ and P ₂ is freely introduced into the pressure chambers 8a and 8b.

On the outer circumferential surfaces of the respective pistons 7a and 7b formed at both ends of the rack 6, two packings 30 and 31 are provided, each of which is in airtight sliding contact with the hole surface of the cylinder hole 5, respectively. These packings 30 and 31 have a function as a piston packing for dividing the two pressure chambers 8a and 8b on both sides of the rack 6, but the packing 30 located on the outside is other than that. It also has a function as a cushion packing for switching the exhaust passage. That is, when the rack 6 is driven in a reciprocating manner, the cushion packing 30 of the pistons 7a and 7b on the front side in the moving direction of the rack 6 is located on the exhaust side just before the rack 6 reaches the stroke end. By passing through the port holes 14 and 15, the pressure chambers 8a and 8b are blocked between the ports P ₁ and P ₂ , and the exhaust gas in the pressure chambers 8a and 8b is discharged only from the exhaust port 19. To work.

The operation of the rotary actuator 1A having the above configuration will be described. In the state of FIG. 1 in which the rack 6 is at one stroke end, when compressed air is supplied to the first port P ₁ , the compressed air is introduced into the valve chamber 24 from the passage hole 26. Since the check valve 23 is opened by pressurization, it flows into the 1st pressure chamber 8a from the exhaust port 19, and the said rack 6 starts moving toward the right side of FIG.

In addition, if the outer packing 30 of the first piston 7a located on the rear side in the moving direction of the rack 6 exceeds the port hole 14 of the first port P ₁ , the compressed air is mainly Since the first pressure chamber 8a is to be directly supplied through the port hole 14, the movement of the rack 6 is continued as it is. At this time, the compressed air in the second pressure chamber 8b on the front side of the rack 6 in the moving direction is mainly discharged directly from the port hole 15 through the second port P ₂ .

In addition, when the rack 6 is close to the forward stroke end and the packing 30 on the outside of the second piston 7b located on the front side in the moving direction passes through the port hole 15, The second pressure chamber 8b and the second port P ₂ are shut off, and the air in the second pressure chamber 8b is discharged from the exhaust port 19 via the flow rate adjusting mechanism 20. In other words, the exhaust port 19 and the throttle hole 22 are formed from the state in which the packing 30 functions as cushion packing and directly discharges the exhaust path through the port hole 15 and the second port P ₂ . It is switched to the state of limited discharge via).

For this reason, the pressure in the 2nd pressure chamber 8b rises by the flow volume restriction by the said throttle hole 22, and this becomes piston back pressure, and reaches the stroke end, decelerating the rack 6. As shown in FIG.

At this time, the cushion packing 30 on the outside of the second piston 7b stops immediately in front of the exhaust port 19, and the piston packing 31 on the inner side stops in front of the port hole 15.

When the rack 6 is retracted from the position of the forward end, compressed air is supplied to the second port P ₂ , and the first port P ₁ is opened to the atmosphere. In addition, when the rack 6 is close to the retract stroke end of Fig. 1, the packing 30 on the outside of the first piston 7a on the front side in the moving direction of the rack 6 functions as cushion packing. The discharge path of the compressed air from the first pressure chamber 8a is discharged directly through the port hole 14 and the first port P ₁ . Since the switch 6 is switched to a state where it is discharged in a limited manner via the throttle hole 22, the rack 6 stops bufferingly while decelerating to the retreat stroke end. At this time, the piston packing 31 inside the first piston 7a stops immediately in front of the port hole 14.

Thus, by supplying compressed air to each of the pressure chambers 8a and 8b from the two ports P ₁ and P ₂ , the rack 6 enters the cylinder holes 5 together with the pistons 7a and 7b. It reciprocates and stops cushioningly at each stroke end by the cushion mechanisms 18a and 18b. In addition, the pinion 10 and the main shaft 11 fixed thereto are reciprocated with the reciprocating movement of the rack 6.

The rotary actuator having the above-described configuration does not need to install a long cushioning ring having a conventional pneumatic cushioning mechanism or a long vacancy in which it is fitted, so that the length in the axial direction of the rack mechanism in the actuator is as short as that. A compact, simple structured actuator can be obtained.

In the case where the rack 6 is buffered to only one of the stroke ends, one of the two cushioning mechanisms 18a and 18b may be omitted.

Fig. 4 shows a second embodiment of the present invention, which is a double rack rotary actuator provided with two racks.

This actuator 1B is provided with two cylinder holes 5a and 5b located in parallel in the cushion 2, and both ends of these cylinder holes 5a and 5b are provided at both ends of the cushion 2, respectively. The second end cover 3 and the second end cover 4 are closed. In addition, inside the two cylinder holes 5a and 5b, the first rack 6a and the second rack 6b, which hold the pistons 7a and 7b at both ends, are slidably accommodated. The pinion 10 is engaged with 6a and 6b, and the main shaft 11 is connected to this pinion 10.

On both sides of the two racks 6a and 6b, the first pressure chamber 8a and the second pressure chamber 8b are formed by the pistons 7a and 7b, respectively, and these pressure chambers 8a and 8b. Two ports P ₁ and P ₂ for supplying compressed air to the c) are provided in the first end cover 3. Among them, the first port P ₁ communicates with the through hole 35a to the first pressure chamber 8a of the first rack 6a, and the second pressure chamber 8b of the second rack 6b. ) Through a through hole 36b provided in the first end cover 3, a through hole 37b provided in the cushion 2, and a port hole 39b opened in the hole surface of the cylinder hole 5b. The second port P ₂ on the other side communicates with the passage hole 35b through the first pressure chamber 8a of the second rack 6b, and the first port 6a of the first rack 6a. 2 Ports opening in the pressure chamber 8b, the through hole 36a provided in the first end cover 3, the through hole 37a provided in the cushion 2, and the hole surface of the cylinder hole 5a. It communicates through the hole 39a.

In addition, in this actuator 1B, as shown in FIG. 5, the first and second two sets of cushioning mechanisms 18a for buffering the two racks 6a and 6b to one stroke end, respectively, are provided. 18b) is provided, and the exhaust port 19 and the flow rate adjustment mechanism 20 in these cushion mechanisms 18a and 18b are provided in the said 2nd end cover 4, respectively. In addition, the exhaust port 19 of the first cushion mechanism 18a corresponding to the first rack 6a opens in the second pressure chamber 8b of the first rack 6a, and the second rack 6b. The exhaust port 19 of the second cushion mechanism 18b corresponding to the opening is opened in the second pressure chamber 8b of the second rack 6b, and each of the exhaust ports 19 is the flow rate adjusting mechanism ( 20 and through holes 40 are connected to the through holes 37a and 37b in the cushion 2.

In addition, although the said flow regulating mechanism 20 consists of the throttle hole 22, and the check valve 23 is connected in parallel with this throttle hole 22, although it is the same as the said 1st Example, the said throttle Since the direction of the flow of the exhaust air passing through the hole 22 is opposite to that of the first embodiment, the direction of the check valve 23 is made opposite to that of the first embodiment.

Outward and inward of the second piston 7b facing the second pressure chamber 8b among the first and second two pistons 7a and 7b formed at both ends of the racks 6a and 6b. Two packings 30 and 31 are provided so that the outer packing 30 functions as a cushion packing, and the other first piston 7a facing the first pressure chamber 8a is lip Only the seal piston packing 31 is provided.

43 is an adjustment screw for adjusting the position of the stroke ends of the racks 6a and 6b, and the tip is placed at a position corresponding to each of the racks 6a and 6b of the second end cover 4 at a second pressure. It is screwed so as to be able to face forward and backward in the seals 8a and 8b.

The rotary actuator 1B of the second embodiment operates as follows. 4 shows a state in which compressed air is supplied to the second port P ₂ and the first port P ₁ is opened to the atmosphere. At this time, the compressed air flows into the first pressure chamber 8a of the second rack 6b through the through hole 35b and also passes through the second pressure chamber 8b of the first rack 6a. It flows in through 36a, 37a and the port hole 39a, moves the 2nd rack 6b to a forward stroke end, and moves the 1st rack 6a to a retraction stroke end.

When compressed air is supplied to the 1st port P ₁ from this state, and the 2nd port P ₂ is opened to air | atmosphere, the compressed air of the said 1st port P ₁ of the 1st rack 6a The check valve 23 is pushed into the first pressure chamber 8a through the passage hole 35a and is also pressed into the second pressure chamber 8b of the second rack 6b from the passage holes 36b and 37b. It opens and flows in through the exhaust port 19, advances the said 1st rack 6a, retreats the 2nd rack 6b, and rotates the pinion 10 and the main shaft 11 in the clockwise direction of FIG. If the packing 30 on the outside of the second piston 7b in the second rack 6b exceeds the port hole 39b, the compressed air is mainly passed through the port hole 39b in the second pressure chamber. It is to be supplied directly to 8b.

When the first rack 6a is close to the forward stroke end and the packing 30 on the outside of the second piston 7b passes through the port hole 39a, the second pressure chamber 8b and the second port (P ₂ ) is cut off, and the compressed air in the second pressure chamber 8b is restricted to be discharged from the exhaust port 19 via the throttle hole 22. Therefore, the first rack 6a reaches the forward stroke end while decelerating, followed by the second rack 6b while reaching the retreat stroke end while decelerating.

When the first rack 6a reaches the forward stroke end, the packing 31 inside the second piston 7b stops immediately in front of the port hole 39a.

When the first rack 6a is retracted and the second rack 6b is advanced to the switched state of FIG. 4, the first port P ₁ is opened to the atmosphere to open the second port P _2. Supply compressed air. At this time, the cushioning mechanism 18b on the side of the second rack 6b is moved, and both racks 6a and 6b are interlocked and bufferedly stopped at their respective stroke ends.

6 to 8 show another example of the cushion mechanism applicable to the present invention. The cushion mechanism 18 shown in FIG. 6 differs from the first and second embodiments in that the throttle hole 22 in the flow regulating mechanism 20 is a fixed shrink type having no needle.

In addition, in the cushion mechanism 18 shown in FIG. 7, the flow rate adjustment mechanism 20 and the check valve 23 are combined with the block 45 different from the casing 2, and this block 45 is a casing 2 ), Which is different from the first and second embodiments described above.

In addition, the cushion mechanism 18 shown in FIG. 8 forms the throttle hole 22 in the flow regulating mechanism 20 directly in the casing 2 by using the exhaust port 19 to form the opening area in the needle. In addition to being variable, a part of the plurality of packings 30 and 31 provided on the pistons 7a and 7b of the rack 6 has a function as a check valve. That is, the outer packing 30 is a seal of the lip seal type which has a directional seal, and this packing 30 is made into the 1st pressure chamber 8a side or the 2nd pressure chamber from the inner packing 31 side. Although the flow of compressed air toward (8b) side is allowed, it is provided in the direction which interrupts the flow of air in the reverse direction.

Therefore, when compressed air is supplied to the second port P ₂ from the state of FIG. 8, part of the compressed air flows into the second pressure chamber 8b from the throttle hole 22, but most of the compressed air Since it flows into the clearance gap of the piston 7b from 15, and presses and opens the said packing 30, it enters into the 2nd pressure chamber 8b, and the rack 6 starts at the desired speed. In addition, after the packing 30 passes through the port hole 15, the compressed air is introduced into the second pressure chamber 8b directly from the port hole 15, and then the packing 30 is And piston packing to preserve the sealability of the second pressure chamber 8b.

6 to 8 are representatively shown as a cushion mechanism on the second port P ₂ side as an example applicable to the first embodiment of FIG. 1, but on the first port P ₁ side. The cushion mechanism also has the same configuration. Incidentally, when the cushion mechanism 18 is applied to the second embodiment of Fig. 4, it is needless to say that the flow rate adjusting mechanism 20, the check valve 23, the exhaust port 19 and the like are provided in the end cover. none.

The present invention provides a rack pinion type rotary actuator having a pneumatic cushioning mechanism, and furthermore, a rack pinion type rotary actuator having a long length in a direction orthogonal to a rotational spindle structurally, can be further lengthened by installing the cushioning mechanism. By eliminating the long cushioning and the long vacancy in which it is fitted, it is possible to provide a rotary actuator with a compact, simple structure and inexpensive rack and pinion type cushioning mechanism.

Claims (11)

One or more cylinder holes installed in the casing; A rack having pistons at both ends and sliding in the cylinder hole by these pistons; A pinion that engages the rack, and a spindle coupled to the pinion; Two ports for supplying compressed air to pressure chambers on both sides of the rack; A port hole opening in the hole surface of the cylinder hole to communicate each port with a corresponding pressure chamber respectively; A cushioning mechanism for buffering the rack at a stroke end of at least one of the forward and reverse sides, The cushion mechanism is provided on an exhaust port opening in the pressure chamber at a position closer to the pressure chamber tip than the port hole, a flow rate adjusting mechanism for restricting the flow rate of exhaust gas discharged from the exhaust port, and an outer peripheral surface of the piston. And a cushion packing operable to block the port hole from the pressure chamber immediately before reaching the stroke end, and to discharge air in the pressure chamber from the exhaust port through the flow rate adjusting mechanism. The rotary actuator with cushion mechanism according to claim 1, wherein the exhaust port is connected to one port through the flow rate adjusting mechanism. 2. The flow rate adjusting mechanism according to claim 1, wherein the flow rate adjusting mechanism is formed of a throttle hole for limiting the flow rate of the exhaust gas discharged from the pressure chamber, and in parallel with the throttle hole, the flow of the exhaust gas discharged from the pressure chamber is prevented and the pressure is prevented. A rotary actuator with cushion mechanism, characterized in that a check valve is provided to allow flow of air supply to the seal. 4. The lip seal according to claim 3, wherein a valve chamber is formed in the casing to connect the exhaust port and the port, and a hole member for holding the throttle hole in the valve chamber forms the check valve between the seal wall. The throttle hole and the check valve are combined in the valve chamber by being inserted and accommodated, wherein the rotary actuator with a cushion mechanism is provided. The rotary actuator with cushion mechanism according to claim 1, wherein the actuator is a single rack pinion type rotary actuator having one cylinder hole and one rack. 6. The cushioning mechanism according to claim 5, wherein the actuator has two sets of cushioning mechanisms, and these cushioning mechanisms are provided at both ends of the casing to buffer the rack at both forward and backward stroke ends. Rotary Actuator. The rotary actuator with cushion mechanism according to claim 1, wherein the actuator is a double rack pinion type rotary actuator having two cylinder holes and two racks. Two cylinder holes arranged in parallel in the casing; First and second racks having pistons at both ends and sliding in the respective cylinder holes by these pistons; A pinion that engages the rack, and a spindle coupled to the pinion; A first pressure chamber and a second pressure chamber respectively partitioned on both sides of each rack; A first port communicating with the first pressure chamber of the first rack and the second pressure chamber of the second rack, and a second port communicating with the first pressure chamber of the second rack and the second pressure chamber of the first rack; Has two sets of cushioning mechanisms for buffering both racks at one stroke end, respectively; The cushioning mechanism includes an exhaust port opening in the second pressure chamber at a position near the end of the pressure chamber rather than a port hole connecting the port and the second pressure chamber, and a flow rate adjusting mechanism for restricting the flow rate of exhaust gas discharged from the exhaust port; And installed on an outer circumferential surface of the piston so as to shut off the port hole from the second pressure chamber immediately before the piston reaches the stroke end to discharge air in the second pressure chamber from the exhaust port through the flow adjusting mechanism. A rotary actuator with cushion mechanism, characterized by having a cushion packing. 9. The casing according to claim 8, wherein the casing has end covers at both ends thereof, and the two ports are provided at one first end cover, and the two second end covers are provided with the two sets of cushioning mechanisms. In addition to the combination of the flow rate adjusting mechanism, the exhaust port opening in the second pressure chamber is provided, and the port and the flow rate adjusting mechanism communicate with each other through a through hole formed in the first end cover and the casing. A rotary actuator with a cushioning mechanism, characterized in that the port hole branches from the through hole of the casing and is opened in the hole surface of the cylinder hole. 10. The flow rate adjusting mechanism according to claim 9, wherein the flow rate adjusting mechanism is formed of a throttle hole for limiting the flow rate of the exhaust gas discharged from the pressure chamber, and in parallel with the throttle hole, the flow of the exhaust gas discharged from the pressure chamber is blocked and the pressure is reduced. A rotary actuator with cushion mechanism, characterized in that a check valve is provided to allow flow of air supply to the seal. 11. The lip according to claim 10, wherein a valve chamber communicating with the exhaust port and the port is formed in the first end cover, and a hole member holding the throttle hole in the valve chamber forms the check valve between the seal wall. A rotary actuator with cushion mechanism, characterized in that the throttle hole and the check valve are combined in the valve chamber by inserting a seal.